1. Field of the Invention
The invention in general relates to a powerline system and more particularly to a system which also carries information via the powerline.
2. Description of Related Art
In a powerline system electrical energy produced at a first location is delivered via the powerlines to a load at a remote second location. In one type of powerline system the load may be an electrical device such as a motor which drives a mechanical device such as a pump. For example, in the field of mining or oil production an electro-submersible pump is often utilized for pumping fluid such as water or oil.
In many such systems it is desirable to be able to know certain operating conditions at the electro-submersible pump location. Accordingly one or more sensors are positioned to obtain indications of these operating conditions, for example, temperature, pressure, etc., and this information is transmitted back to a receiver system along the powerline conductors, usually as dc signals.
In order to accomplish this signal transmission, the powerline neutral must be ungrounded since a grounded neutral point would short out the information signals. If a powerline ground fault does occur it would be desirable to have a grounded system to protect the powerline conductors and other components.
These seemingly contrary objectives are met by the present invention.